User's Manual

147
When we speak of free software, we are referring to freedom,
not price. Our General Public Licenses are designed to make
sure that you have the freedom to distribute copies of free
software (and charge for this service if you wish), that you
receive source code or can get it if you want it, that you can
change the software or use pieces of it in new free programs;
and that you know you can do these things.
To protect your rights, we need to make restrictions that forbid
anyone to deny you these rights or to ask you to surrender the
rights. These restrictions translate to certain responsibilities for
you if you distribute copies of the software, or if you modify it.
For example, if you distribute copies of such a program,
whether gratis or for a fee, you must give the recipients all the
rights that you have. You must make sure that they, too, receive
or can get the source code. And you must show them these
terms so they know their rights.
We protect your rights with two steps: (1) copyright the
software, and (2) o󱐯er you this license which gives you legal
permission to copy, distribute and/or modify the software.
Also, for each author’s protection and ours, we want to make
certain that everyone understands that there is no warranty for
this free software. If the software is modied by someone else
and passed on, we want its recipients to know that what they
have is not the original, so that any problems introduced by
others will not reect on the original authors’ reputations.
Finally, any free program is threatened constantly by software
patents. We wish to avoid the danger that redistributors of a
free program will individually obtain patent licenses, in e󱐯ect
making the program proprietary. To prevent this, we have made
it clear that any patent must be licensed for everyone’s free use
or not licensed at all.